Supervisory signal for telephone-switchboards.



New STATES PATENT OFFICE.

FRANK a. MGBERTY, or DOWNERS GROVE, ILLinoIs, ASSIGNOR To THE WESTERN ELECTRIC COMPANY, or CHICAGO, ILLINOIS.

:SUPERVISORY SIGNAL. Foe 'lE LEPHOTN E-SWITCHBbARDS.

'sjrno'rrroarzon forming wt of was Patent No. 654,747, eta July 31, 1900.

Application file (l N6veinber13,1897. serial No. 658,398. (No model.)

To aZZ whom it may concern.-

Be it known that I, FRANK R. MUBERTY, a citizen of the United States, residing at Downers Grove, in the county of Du Page and State of Illinois, have invented a certainnew and useful Improvement in Supervisory Signals for Telephone-Switchboards, (Case No. 55,) of which the following is a full, clear, concise,

and exact description, reference being had I o to the accompanying drawings, forming a part of this specification.

This invention is a general or pilot signal for use in telephone-switchboards in association with supervisory signals referring to united lines.

In certain well-known types of switchboard for switching telephone-lines into connection with each other each line is provided at its substation with means for changing the as strength of a signaling-current in the line incidentally in the use of the telephone, and the link-conductors employed for unitinglines in the switchboard are equipped with signals responsive to such currents through each of two united lines, which accordingly indicate to the operator the condition of use or disuse of the station instruments of the lines. The simultaneous indication of the signals that the station-telephones of two united lines are 0 no longer in use is accepted by the attendant as a clearing-out signal, and the connection between the lines is broken.

The object of thisinvention is to provide for a bank or equipment of such pairs of supervisory signals attended by one operator a general or pilot signal whose display is conditioned by the simultaneous operation of both supervisory signals associated with one link-conductor, or, in efiiect, with one pair of united lines.

To this end it consists in the combination, with two or more supervisory signals, of a general signal and mechanism made operative through the simultaneous operation of the supervisory signals to'actuate the general signal, and in the combination, withseveral pairs or groups of supervisory signals, of a general signal and mechanism made operative through the simultaneous operation of the members of any group of supervisory signals to actuate the general signal. In the .all the breaks in some one bridge by the operationof all the signals in the corresponding group.

The attached drawings are illustrative of the invention.

Figure 1 of. the drawings represents two telephone-lines extending from substations to a central station and terminating there in spring-jacks, in connection with a pair of plugs and their uniting plug-circuit for linking the lines into a continuous circuit. Two supervisory signals are associated with the plug-circuit and these control a general signal. Fig. 2 illustrates in asimplified manner the mode of bringing the general signal under the control of a number of pairs of supervisory signals of difierent plug-circuits.

Referring to Fig. 1, each substation A is equipped with a bell b, a transmitting-telephone I) and receiving-telephone b and a switch 19 for closing the circuit of the line through the telephones during their use. These appliances are connected by line conductors 1 and 2 with a spring-jack c in the switchboard, the two line conductors being led to two contact-terminals o and c of the spring-jack. The springjack is equipped also with a third contact-piece c which is represented as being grounded. The appliances by means of which the subscriber may initiate a call in the switchboard are not shown, inasmuch as they are well known, and, further, the devices which are usually included in the ground connection of the local contact-piece c of the spring-jack are also omitted from'the drawings, being represented by the coil d. Pairs of plugs c and e are provided for the use of the operator in uniting lines by means of their spring-jacks. Each plug consists of three contact-pieces, which are designed to register with the local contact 0 and the line-contacts c and 0 respectively, of a spring-jack. Like contact-pieces of the two plugs are united by conductors 3, 4, and 5, respectively, the first two-of which consti-' tute the plug-circuit. The switch-contacts I of a calling-key f are interposed in the conductors of the plug-circuit. It will beunderstood, further, that the plug-circuit would in practice be equipped with an operators .1is-.

tening-key for bringing a telephoneinto c0 n nection with the plug-circuit. A conductor 6, which forms a bridge of the plug-circuit,

includesa battery g. Impedance-coils h and.

h are interposed between the poles of the battery and the corresponding conductors of the plug-circuit. The conductor a is formed in part of the magnet-windings of two relays;

t and i, one winding being at each side of the. bridge 6 of the plug-circuit, so that each relay is responsive only to current through the tele:

phone-line with which it is immediately connected, Theserelays control each a secondary supervisory signal, these signals, being designated k and 70, respectively, in the i'ollowing manner: The windings of the signals k and 1c are included in the conductor 5. The middle point of. this conductor between these windings is connected with a pole of a battery 1, whose other pole is grounded. The signal his. designed to refer to the plug 2 or to the line with which that plug is connected,

while the signal 70 refers to the plug 6'. The supervisory relay 2' controls a short circuit 7 about the magnet-winding of signal it, while the relay 1" similarlycontrols a short circuit of the signal 7t,.the relays being-adapted to close the shortcircuits about the signals when the relaysare excited.

The signal it may be of any well-knowntype 7 having an indicator which becomes displayed supervisory signals I add to the signal Isa when the magnet of the signal is excited. I have found the, signal described in Patent No. 536,10 i, dated March 19, 1895, to Theodore Spencer, eminently suitable for this use.

In applying the present invention tojthese contact-piece m, connected with its armature or some otherportionwhich is moved in the excitement of the magnet, which is designed. to impinge upon the contact-anvil'mflwhen.

the armature is attracted. These switch contacts of thetw'o supervisory signalskand 7c of a'singlepair of plugs are included in a local circuit 8, together with a battery it,

which includes also the general or pilot signal o. The most eflicient pilot-signal is an incandescent lamp...

I do not deem it necessary to describe in detail the well=known stepsof signaling to the central ofiice from a substation and making connection, at the central office between the calling line and theline called for by. means of plugs e and e inserted in the spring-jacks of. the respective lines. After the. connection has been established the bat tery g in the bridge 6 of the plug-circuit tendsto produce a flow of current in each of v the lines tostations A andA', the flow of current in these lines being determined, howeverpby thereby hidden.

l the position of the switches at the respective stations, the current being permittedto flow only when the substation-telephone is removed from its switch-hook for use. The act of placing the plugs e and e" in the springjacks' of the lines completes not only the connection between the lines through the agency of the plug-circuit, but also local circuits made up of conductors 5, terminating in the sleeves of plugs e and .e and the conductors terminating in the correspondingring-contacts c of the spring-jacks. The complete local circuitof battery Z, closed inthe contact-pieces of each plug and spring-jack,

tends-to-cause the excitement of the signal .7a or. k in the same circuit. In the ordinary course ofevents, however, the telephoneat the calling station. A, for example, will have been removed from its switch-hook in the process of signaling to the exchange forconnection, so that when the. plug. is inserted inthe spring-jack of thecalling, line. current from battery 9 immediately finds circuit through the line conductors, the switch besignal k. This signal accordingly. remains inert and concealed. Since its armature is not attracted. toit's magnet, the local circuit 8 remains open at the switch-contacts 'm m of signal It and the pilot-signal 0 is'not. lighted. Until the subscriber at the called. station takes his telephone for use the relay t" refer;

ring to that line is notexcited',.so thatjcurrent from-battery Z through the local circuit 5 corresponding to that line excites the signal is ing closed at the station, whereby the relay i is excited and closes a short. circuit. of the and keeps its indicator in View. During con.-

'versation between the subscribers, however,

the linecircuits areof courseclosed at their respective stations and both signals 7c and 7c are short-'- circuite.d,.their I. indicators being Whenatthetermination of conversation both staticn-telephones are replaced on their switches andthe-line-circuits ,are opened at the stations, the relays i-and i are deprived of current, they release. their armatures,breakingthe shunts about signals k and k, the magnets of the signals areexcited, the armatures are drawn forward, and .the signals aredisplayed,..whi1e.at the same time. the. two breaks in the local circuit .8 are closed and the pilot-signal 0 becomes lighted by current thus createdin the circuit. l The operators attention will be first attracted to the pilot-signal, andthus directed to. the pair of supervisorysignalslc and 7c, whicharedisplayed. Acting upon this call for disconn'ec tion she will then remove theplugsfrom the spring-j acks and return the appliances totheir normal positions.

- It is understood that, each operator .at a telephone-switch is equipped with a considerable number of pairs of. plugs, eachpair with its associated signals k and 70",.the entire bank of signals being in connection with asingle piloiksignalo... The .circuitpf a pilot-signal thus associated with a considerable number of supervisory signals is shown in Fig. 2.

The local circuit, which was designated 8 in the description of Fig. 1, consists, in fact, of two main conductors 9 and 10, which include the pilot-signal 0, and are connected with the poles of a battery 92. These conductors are connected together by several branches or bridges 11, one for each pair of supervisory signals. Each bridge 11 traverses in series the switch-contacts m m of both supervisory signals is and k of one pair. Obviously the completion of both breaks in any bridge 11 of the circuit,inclnding the pilot-signal in the simultaneous display of both members of the pair of supervisory signals to call for disconnection, will cause the display of the pilotsignal 0 and call the attention of the operator to the particular pair of supervisory signals thus displayed, whereupon she will disconnect the corresponding lines.

This mode of controlling a pilot-signal in association with pairs or groups of supervisory signals referring to different pairs of plugs is of course not confined to its use in connection with supervisory signals of the particular arrangement herein described, c0nsisting of a special visible signal and a relay controlling the signal.

Various changes in the arrangement of parts may be made without departing from the spirit of the invention.

The invention is defined claims:

1. The combination with united telephonelines and a signal associated with each line and controlled by current in the line, of a pilot-signal and mechanism actuated in the simultaneous operation of the said signals adapted to cause the display of the pilot-signal, as described.

2. The combination with united telephonelines,

in the following mining the flow of current in the line in the each provided with means for deteruse thereof, of an electromagnet controlled by current in each line, and switchcontacts actuated by each magnet to be closed when the said magnet is excited, a signal, and a circuit including serially the contacts of both of said magnets, together with said signal and a source of current, as described.

3. The combination with pairs of united telephone-lines, and a supervisory signal for each line controlled by current therein determined in the use of the line, of a pilot-signal, a circuit including the pilot-signal, different bridges in multiple of the said circuit, and switch-contacts on each supervisory signal adapted to be closed thereby in one position, the switch-contacts of both members of a pair of supervisory signals being included serially in each of said bridges, substantially as described.

4. The combination with telephone-lines each having a switch at its substation for cl0sing the line during the use of the telephone, of plugs and plugcircuits uniting the lines in pairs, a bridge of each plug-circuit including a source of current, a relay in the circuit of each line, a supervisory signal associated with each line in a local circuit controlled by the corresponding relay, a pair of switch-contacts on eachsuper'visory signal actuated thereby to be closed when the signal is displayed, a general or pilot signal, a local circuit including the pilot-signal, together with a source of current, and normally-open bridges adapted to complete the said local circuit, each of said bridges including serially the switch-contacts of supervisory signals of united telephonelines, as described.

In witness whereof I hereunto subscribe my name this 10th day of September,A. D. 1897.

FRANK R. MCBERTY.

Witnesses:-

JOHN W. SINCLAIR, A. L. LAWRENCE. 

